Cantilever mounted sliding and swinging door

ABSTRACT

1,263,137. Door with sliding and swinging movement. STANLEY WORKS. 3 April, 1969 [12 April, 1968], No. 9810/71. Divided out of 1,263,136. Heading E1J. The description is the same as for the Parent Specification 1,263,136 but the claims are directed to the feature of the sliding and swinging door assembly wherein opening of side panels 21 by the operation of the sliding panels 23 is effected when these latter partake of a swinging movement to engage the free edges of the side panels 21 to pivot the latter panels so as to give complete access through the opening in the building, e.g. in the case of an emergency or panic to clear the interior of the building of people.

.4 Sheets-Sheet 1 N at Q... L

ROBERT A. MILLER Jan. 27, 1970. R. A. MILLER CANTILEVER MOUNTED SLIDING AND SWINGING DOOR Filed April 12, 1968 ATTORNEYS Jan. 27, 1970 RA. MILLER CANTILEVER MOUNTED SLIDING AND SWINGING DOOR Filed April 12, 1968 .4 SheetsSheet 2 Jan. 27, 1970 R. A. MILLER CANTILEVER MOUNTED SLIDING AND SWINGING DOOR .4 Sheets-Sheet 5 Filed April 12, 1968 R. A. MILLER 3,491,483

CANTILEVER MOUNTED SLIDING AND SWINGING DOOR Jan. 27, 1970 .4 Sheets-Sheet 4 Filed April 12, 1968 United. States Patent US. Cl. 49-141 19 Claims ABSTRACT OF THE DISCLOSURE A trussed trolley extends substantially the full width of a swinging and sliding door panel to support the panel from an overhead track. The supporting connection between the door panel and the trolley comprises a rigid downwardly extending journal bearing secured adjacent one end of the trolley and a mating vertical shaft secured in the stile of the door panel to provide a vertical cantilever pivot connection for supporting the door as the panel is pivoted during breakout from a position coplanar with the trolley, eliminating the need for support against sag by a bottom pivot. The trussed trolley includes an extension beyond the pivot axis of the door panel and pairs of adjustable compression and tension screws disposed on opposite sides of the pivot rigidly secure a reinforcing bar of the trussed trolley and are adjustable to deflect the end of the reinforcing bar to adjust the pivot axis of the panel as well as the vertical position of the-panel. A side panel disposed outside of the sliding panel is mounted on fixed pivots adjacent the door jamb and is resiliently biased to its closed position. The free end of the side panel overlaps the pivot axis of the sliding panel in its closed position and is automatically engaged by the sliding panel during breakout so that the sliding panel may be pivoted outwardly a full 90 whether the sliding panel is at its open or closed position, or at any intermediate position. The sliding panel is power operated and includes controls to assure that the side panel must be unlocked during automatic operation and that the power operator is inactive during breakout.

This invention relates to a building access or interior door which normally operates in the sliding mode in response to trafiic therethrough but may also operate as a swinging door under low trafiic conditions or as an emergency measure in the event of power failure or malfunction of the automatic mechanism.

An object of this invention is to provide a sliding door which has a track on the inside of the building and meets the requirements of building and fire codes for an emergency exit. Included in this object is the provision of such a door which may be swung outwardly at any point along its sliding travel from its fully closed to its fully open position.

Another object of this invention is the provision of a sliding door of the type described wherein the doorway may be opened to substantially twice its normal width for the passage of large objects therethrough.

A further object of this invention is to provide a sliding door of the type described wherein the door is supported against sagging during swinging operation without the need for a lower pivot. Included in this object is the provision of a trussed trolley mounting the door for its sliding mode of operation and providing a cantilever sup port for the door during its swinging movement.

Still another object of this invention is to provide a sliding door of the type described having novel means for adjusting the cantilever support for the door into permanent parallelism with the floor.

3,491,483 Patented Jan. 27, 1970 An additional object for this invention is to provide a sliding door of the type described having controls for assuring conformance with the requirements of building and fire codes at all times during its automatic mode of operation.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which is exemplified in the construction hereafter set forth, and the scope of the invention is indicated in the appended claims.

' In the drawings:

FIG. 1 is a somewhat diagrammatic front elevation view of an exemplary embodiment of the invention including a pair of door panels horizontally slidable with respect to a pair of side panels;

' FIG. 2 is a schematic top view of the door assembly of FIG. 1;

FIG. 3 is an enlarged fragmentary cross-section view taken along lines 33 of FIG. 1;

FIG. 4 is an enlarged fragmentary side view, partly in section and partly broken away, of the upper portion of a sliding door panel and the cantilever support thereof; FIG. 5 is an enlarged fragmentary view taken along lines 5-5 of FIG. 1 showing a door catch at the free end of the sliding door panel;

FIG. 6 is a fragmentary end view partly broken away of the door latch of FIG. 5;

FIG. 7 is an enlarged fragmentary view taken along lines 77 of FIG. 1 showing a lower guide design for the sliding door panel;

- FIG. 8 is a fragmentary side view partly in section of the lower guide of FIG. 7; and

FIG. 9 is a schematic control circuit for a power operator for the sliding panels.

Referring now in detail to the drawings, a sliding door structure is generally shown at 10 in FIGS. 1 and 2. Sliding door structure 10 selectively opens and closes a portion of the door opening defined by a pair of vertical jamb members 15 spaced horizontally from one another, a horizontal header 17 secured to the jamb members and interconnecting them, and a sill 19.

The door opening is partially closed by a pair of nonslidable panels 21 which may or may not be transparent. The remaining portion of the door opening is selectively opened and closed by a pair of slidable door panels 23. The slidable panels 23 are mounted to slide in a plane parallel to the plane of the non-slidable panels 21 on an overhead track 25 inside the building and overlap the panels 21 when in the open position. The slidable panels 23 are also mounted to pivot about a vertical axis as hereinafter more fully described.

The header 17 is an elongated metal box member of substantially rectangular cross section and houses the track 25 extending longitudinally therein between the sides of the door opening. The header 17 may be of any suitable construction such as that disclosed in my copending application Ser. No. 690,972, filed Dec. 15, 1967 which provides a longitudinally extending slot in the lower face thereof to receive the upper portion of the trolley 27 for movement along the track 25.

As hereinafter more fully described, each of the door panels 23 is cantilever mounted by the trolley 27 by a vertical cantilever support and pivot assembly 29 adjacent an upper vertical edge of the door panel 23. The cantilever support and pivot assembly 29 is constructed and arranged to carry without sag the unbalanced weight of the door panel 23 during sliding movement of the door panel 23 and as the panel is pivoted from its position coplanar with the trolley 27 during swinging operation.

It is essential that a sliding building access door be capable of being swung outwardly under all emergency conditions such as power failure, operator malfunction, or panic conditions to meet the safety requirements of fire and building codes. In accordance with one aspect of this invention, these safety requirements are met and exceeded by the design of this invention when the door is fully closed, fully opened and when the sliding panel is at any intermediate position therebetween despite the fact that the sliding panel 23 is slidable on a track on the inside of the building relative to side panel 21 to protect the track from exposure to the elements.

If the normally slidable door panel 23 is closed and is swung outwardly on the pivot axis provided by the cantilever support and pivot assembly 29, such swinging movement automatically causes the outer surface of the panel 23 to engage the free swinging edge of the side panel 21 to enable the door panel to swing outwardly to provide the full, normal width of the doorway for the exit of traflic. As shown, a door closer 35, which may be concealed or exposed as desired, is provided for the side panel 21 to bias the door panel 21 to its closed position by a biasing force which may be readily overcome by the swinging panel 23 during swinging movement thereof.

As shown in the phantom lines in FIG. 2, the same swinging mode of operation of sliding panel 23 may be effected when the sliding panel is partially opened or fully opened due to the engagement of the free edge of the pivoted side panel 21 by the panel 23 when panel 23 is disposed at any position along its sliding path. Since the cantilever support and pivot assembly 29 is capable of serving as the sole support for the unbalanced weight of the sliding panel 23 from the overhead trolley as the panel 23 is swung from its normal position coplanar with the trolley 27, no pivot is required at the bottom of the slidable panel 23 as the panel 23 is swung from its normal position. This eliminates the need to provide a vertical supporting member suspended from the trolley to mount a lower pivot, or another arrangement to lock or fix the position of a lower pivot transversely of the doorway in alignment with its pivot axis to support panel 23 during breakout.

As indicated above, this invention contemplates that each of the door panels 23 is cantilever mounted by the trolley through the vertical cantilever support and pivot assembly 29 adjacent the upper vertical edge of the door panel 23.

Referring principally to FIGS. 3 and 4 of the drawings, the invention utilizes a trussed trolley member 27 which overlies the door and extends along the track a distance substantially equal to the width of the swinging panel 23. As illustrated, the trussed trolley 27 comprises an extruded trolley housing 28 having trolley wheels 37 adjacent the ends thereof for rolling along the track 25. A pair of vertically adjustable bumpers 39, or limit stops, positioned in close proximity to the lower side of the track 25 by adjusting screws 41 are provided to prevent the derailing of the trolley in the event of the sudden change ofspeed thereof.

As best shown in FIG. 3, a U-shaped channel member 43 is adjustably positioned over the lower portion of the trolley extrusion 28 for relative vertical telescopic movement with the side walls of the channel member 43 engageable with the side walls of housing 28. Channel member 43 has a length substantially the same as the trolley housing 28. The U-shaped channel member 43 is preferably made of high strength steel and is secured to the trolley housing 28 by a plurality of pairs of screws 45, 47 as hereinafter more fully described, whereby the housing'28 and the channel member 43 mutually reinforce each other 'to form thetrussed trolley 27.

With the door panel 23 secured to the cantilever support and pivot assembly 29, the screws '45 may be adjusted by turning them relative to their nuts 46 having flats confined against rotation in mating axial slot 48 so as to raise and lower the panel 23 to provide the desired clearance with the floor. When so adjusted, the screws 47 may be tightened to rigidly fix the channel member 43 with respect to the extrusion 28. Since the housing 28 is desirably made of aluminum, for ease of fabrication, it is desirable to provide an axially telescoping metal plate 49 mounted and confined in a mating axial slot 51 of the housing 28 to provide a bearing surface for the screws 47.

Referring now particularly to FIG. 4, the vertical cantilever support and pivot assembly 29 will be described. The stile 55 of the door is preferably a rigid structural member such as a rectangular aluminum extrusion having a 2" dimension in the plane of the door and a 1 /2" central bore. As illustrated, the solid steel lower portionof the cantilever support and pivot member 57 is preferably longitudinally grooved and assembled in the extruded bore :62 of the stile S5 with a press fit to rigidly secure the same :therein. One or more dowelv pins 59 may be used to further secure the member 57 in the stile 55. a

As illustrated, upper hollow steel cantilever support and pivot member 61 is fixedly secured to the channel member 43 as by weld 44 and is received in the end of the bore 62 of stile 55 with a close fit. An upwardly extending shaft 63,-which in the illustrated embodiment is formed integrally with the lower cantilever support and pivot member 57, extends through the bore of the upper cantilever support and pivot member 61 to provide a concentric close fitting journal bearing with the bore of the upper member 61. A nut 65 engages the upper threaded end of the shaft 63 to support the gravity weight of the door and a pair of anti-friction bearings,

such as needlebearings 67, are provided so that the nut' 65 may be tightened up sufiiciently to prevent relative vertical movement between the upper and lower cantilever support members 61, 57 while accommodating the relative pivotal movement thereof. By the use of a rigid trussed trolley in conjunction with a cantilever support and pivot assembly having a section modulus sufficient to serve as the sole suport for the door panel 23 as contemplated by this invention, the use of a load carrying lower pivot to prevent the free end of the door panel 23 from sagging may be eliminated. I have found that where the upper cantilever support pivot extends into the bore 62 a distance of about 5 inches and has a wall thickness of A and the shaft 63 is A" in diameter, the construction can support, without perceptible sag, an unbalanced load of 300 ft. lbs. With the vertical positioning of the door adjusted by the pairs of screws 45, 47 asindicated above, it is desirable to adjust the pivot axis of the cantilever support and pivot assembly 29 to true the door panel 23- vvith the doorway.

This invention further provides novel means forachieving this. objective.

Referring to FIG. 4, this is accomplished by extending the trussed trolley 27 a short distance beyond the pivot axis of the cantilever support and pivot assembly 29 to provide. a short overhang of say 2". A pair of adjusting screws 69, 71 engageable with a steel plate 73 axially assembled and retained captive within the slot 51 vof the trolley housing 27 in the same manner as, plate 49 are proyided. By the adjustment and tightening. of the tension; screw 69 and the compression screw 71,. the U-shaped ing screws 69, 71, and the channel member 43 serve as a second-class lever to adjust the pivot axis of the door panel '23 while serving to reinforce the'trussed trolley construction which mounts the "cantilever support and' pivot assembly for the door.

Since the top corner pivotconstruction supports the pivot is not required to support the door as it is moved from a position coplanar with the track. It is, however, desirable to provide means for preventing the bottom of the door from swinging like a barn door due to differential pressures inside and outside the building, as for example, could result from wind conditions. To perform this function, a roller 75 is secured to the lower end of the door to frictionally engage the threshold 77 as illustrated in FIGS. 7 and 8. This roller is preferably formed of a molded plastic material such as a polyurethane so that the roller is quiet, has long wearing characteristics and provides a relatively high friction against lateral movement. As shown, the threshold is provided with stop means to limit the lateral movement of the roller 75 and take the form of one or more extensions 76 on the supporting yoke 78 for the roller 75 which loosely fits into one or more slots 79 in the threshold. Under normal conditions of operation, the extensions 76 do not bear against the sides of the slots 79 which, as shown, are provided with bumpers 81 of a suitable bearing material, preferably formed of a long wearing, tough bearing material having some resiliency such as a vinyl extrusion to provide for quiet operation in the event that the extensions 76 should engage the walls of the slots 79.

The yoke 78 is provided with an upwardly extending cylindrical stem 83 which is rotably mounted in a hollow adjusting screw member 85 which is externally threaded to be received in the mating threads of a collar 87 fixed in the stile 55 of the door in any suitable man-' ner such as by set screws 89. The stem 83 is shown as being provide-d with a fixed cros pin 91 which is normally positioned above the cros slot 93 in the adjusting screw member 85 and a light spring 95 biases the yoke and the roller 75 downwardly against the threshold 77. By virtue of this construction, the roller 75 is biased downwardly against the threshold by substantially constant spring force with the spring 95 accommodating variations in the level of the threshold 77. It is apparent that a single yoke extension 76 received within a slot formed directly in a flush floor, or a raised bead coperating with the roler 75 to limit the lateral movement of the bottom of the door could be used in lieu of the illustrated design in view of the absence of the need for a bottom pivot which must be fixed transversely of the doorway during breakout.

A releasable latch is provided at the free ends of the sliding door panels 23 to fix the position of the door panel during sliding operation. As illustrated in FIGS. 5 and 6, the latch includes a pair of latching members 103 and 105 which have mating tapered tongues which engage each other to position the door panel 23 for sliding operation. The base 108 of latching member 105 is secured to the -U-shaped channel member 43 of the trolley and the base 110 of latching member 103 is secured to the stile 56 of panel 23 by any suitable means such as screws 107, 109 respectively. The latching member 103 includes a spring biased roller 111 mounted by a yoke 113. The tension of the biasing spring 115 may be adjusted as desired by the nut 117 which threadably engages a stem 119 formed integrally with the yoke 113. i

As illustrated, the roller 111 is seated in a recess 121 of the latch member 105 to releasably secure the door panel 23 in position for sliding operation. If desired and as shown, the tongue 104 of latch member 103 may be extended upwardly so as to provide a top surface narrow clearance with the base 108 of the latching member 105 to limit the movement of the panel 23 toward the trolley 27 as a result of a sudden change in the speed of travel of the door panel 23 during its sliding mode of operation.

The portion of the trussed trolley 27 exposed below the header 17 is provided with a decorative cover 123 which is shaped to axially telescope over the exposed portion. As shown in FIG. 5, the cover 123 overlaps the top of the door on the inside of the building but is foreshortened on the outside so as not to interfere with the swinging of the door panel 23 during its swinging mode of operation.

Referring primarily to FIG. 9, there is shown a schematic diagram including the controls of an illustrative embodiment for a power operator for powering the sliding panels 23 during their normal sliding mode of operation.

As illustrated, a suitable power operator includes a fluid supply which delivers fluid under pressure to a power cylinder 132 through a manually operated shutoff valve 134 and selectively through a pair of normally closed solenoid operated control valves 136 and 138 which are connected respectively to the opposite end of the cylinder 132 for opening and closing a door panel 23, it being understood that the piston rod 140 may be mechanically connected to open and close a door panel 23 as for example by being connected to the trussed trolley 27 by a pin 141 (FIG. 4). Where, as in the illustrative embodiment of FIG. 1, the door assembly involves a pair of sliding panels 23, the panels may be connected for simultaneous operation in any suitable manner.

The solenoid control valves 136 and 138 are shown as being provided with an electric control circuit. As schematically illustrated, a singe-throw double-pole master control switch 142 is connected to a source of electrical energy and when closed connects the control circuit to the source. A normally open control switch 144 such as, for example, a carpet switch placed along the trafiic path at the approach to the doorway is connected to energize a control relay 146 to deliver electrical energy to the solenoid of normally closed solenoid valve 136 to deliver pressurized fluid to the cylinder 132 to move the piston thereof in a direction to open the door panel 23. Under these circumstances, the normally closed solenoid valve 138 is not energized and any fluid in the cylinder 132 to the right of the piston may be discharged through the dumping conduit 148.

So long as the switch 144 is closed, the valve 136 will remain open so that the door panel 23 will be held open for the passage of traflic. When the switch 144 returns, or is returned, to its open position, the solenoid for the valve 136 will be deenergized by the relay 146 and the solenoid for the solenoid valve 138 will be energized to open valve 138. Whereupon the door will return'to its closed position due to the entrance of fluid into the right end of the cylinder 132 to move the piston rod 140 to the left as shown in FIG. 9. Since the solenoid valve 136 is deenergized, it is returned to its closed position and any fluid within the left end of the cylinder 132 is dumped through the dumping conduit 150. v

As the door panel 23 reaches its closed position the normally closed limit switch 151 is automatically opened in any suitable manner to deenergizethe solenoid of the valve 138 so that the door remains in its closed position with both solenoid valves 1 36 and 138 deenergized.

In the illustrative controls for the power operator 132, it will be apparent that in the event of either a failure of the electrical power or of the fluid supply for the operator 132, the operator 132 will not be powered to move the panel 23 or hold it in any position.

Where the design of this invention is used as a building access door, it is desirable to provide means for locking the side panels 21 and the sliding panels 23 when the building is not in use. Referring to FIG. 1, this may be accomplished by a key operated lock 152 which axially moves lock pins 154, 156 located in the stile of the door into aligned apertures 158 and 160 located respectively in the header and the sill of the door. The lock 162 is provided to lock the panels 23 together to prevent sliding movement therebetween when the lock is secured. Where a pair of sliding panels 23 are utilized as in the embodiment of FIG. 1, it is desirable to provide a lock pin 164 which extends through the stile 56 of the door panel 23 and is received in an aperture 165 in the sill 19 to prevent G pivotal movement of the panels 23 relative to the trussed trolley 27. It will be understood, of course, that where a single sliding panel 23 is used, the lock 162 engages an immovable jamb at one side of the doorway and the lock pin 164 is not required to secure the door panel 23 against pivotal movement.

When the door panel 21 is locked, it will be apparent that the sliding panel 23 may not be pivoted during breakout, as under panic or emergency conditions since the door panel 21 is not free to swing outwardly. This invention provides means for assuring that the panel 21 must be unlocked whenever the sliding panel 23 is powered by the operator 132 in its automatic mode of operation.

Referring to FIGS. 1 and 9, a normally closed switch 166 which is connected in series circuit relationship with the solenoids for valves 136 and 138 is mounted by the header 17 (FIG. 1) so as to be engaged by the lock pin .154 when the panel 21 is locked by the lock 152. Since the normally closed switch 166 is held open by the 1001-; pin 154 when lock 152 is locked, it will be apparent that neither the solenoid for valve 136 nor the solenoid for valve 138 may be energized when the lock 152. is locked.

The invention further provides means for assuring safety of operation of the swinging and sliding panels 23 during emergency conditions under the automatic mode of operation. As shown in FIG. 9, a normally open switch 168 is connected in series with the solenoids of both valve 136 and valve .138 so that these valves remain closed (i.e. unenergized) whenever the switch 168 is open.

Referring to FIG. 1, the switch 168 is mounted by the header 17 in such a position as to be held in its closed position by a side panel 21. During breakout as the panel 23 is pivoted to pivot the side panel 21 (see FIG. 2), the side panel 21 is moved from its position coplanar with the header .17 to release the switch 168 so that it assumes its normally open position to open the electrical circuit to the solenoids of valves 136 and 138 regardless of whether the door is moving toward its open or closed position. Thus, during breakout of the panels 23, the operator 132 cannot power the sliding panels 23 so that the panel 23 is under the exclusive control or the user who is manually swinging the door panel 23 open.

From the foregoing, it is apparent that with switch 142 open, the panel 23 may be manually operated as a sliding door under low trafiic conditions, as, for example, to permit early morning deliveries or the entrance of employees before the building is open for business. It will also be apparent that a side panel 21 may be unlocked and used as a self-closing manually operated pivoted door which swings outwardly under the same conditions.

From the foregoing, it will be apparent that this invention provides a unique sliding and swinging door suspended from an overhead track so as not to require a bottom pivot during breakout, which does not require a pocket to receive the door at the side of the doorway, which may be open to substantially double its width to permit the entry of wide objects or under emergency conditions and which may be manually or power operated. It is further apparent that the controls for the door when used in its automatic mode or" operation assure that the requirements of the building and fire codes are met or exceeded under all conditions of operation and circumstances, and that the unique trussed trolley and top corner pivot design of the invention further provides for the adjustment of the sliding panel and the pivot axis relative to the trussed trolley.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure abovedescribed will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. In a doorway, a track extending transversely of the doorway, a door panel, and an elongated trolley mounted by the track for movement therealong, the improvement wherein a cantilever mounting connection mounts the panel so that it is selectively movable along the track in a position parallel thereto and pivotable about a pivot axis substantially perpendicular thereto, said cantilever mounting connection consisting of rigid vertical hinge pin means and vertical journal means closely receiving the hinge pin means, one of said hinge pin and journal means being fixed to the door panel adjacent one vertical edge thereof and the other of said means being fixed to the trolley to support the full unbalanced weight of the panel as the panel is pivoted from its parallel position.

2. A device as recited in claim 1 wherein the door panel is provided with a concentric recess about said hinge pin means and said journal means comprises a hollow tube positioned in said concentric recess.

A device as recited in claim 2 wherein the stile of the door panel is an extruded structural member.

4. A device as recited in claim 1 wherein a stop is provided to limit the lateral swinging of the bottom of the door panel relative to the top, the stop providing no support for the unbalanced weight of the door panel in the direction parallel with the track.

5. A device as recited in claim 4 wherein the stop comprises a roller engageable with the threshold of the door panel, the roller being mounted on an axis perpendicular to the track.

6. The device of claim .1 wherein the trolley is a truss construction and the journal means is carried thereby.

7. The device of claim 6 wherein the vertical hinge pin means is provided with an enlarged portion rigidly secured in the stile of the door panel and the hinge pin means projects upwardly from the top of the door panel to be received within the journal means, wherein antifriction thrust bearings are provided at both ends of the journal means, and wherein a fastener is provided at the upper end of the hinge pin means to secure the panel against vertical movement relative to the trolley while accommodating pivotal movement therebetween.

8. A device as recited in claim 1 wherein the trolley includes a trolley housing which extends substantially coextensive with the door panel along the track thereof.

. 9. A device as recited in claim 8 wherein the trolley housing is a continuous extrusion vertically spanning track.

10. A device as recited in claim 9 wherein a releasable latch is carried by the trolley to releasably maintain the panel aligned therewith.

11. A device as recited in claim 8 wherein the trolley includes a bar to which the other of said hinge pin and journal means is secured, and means are provided for vertically deflecting the bar relative to the remainder of the trolley and for rigidly securing the same in adjusted position to adjust the pivot axis of the cantilever mountin g connection.

12. A device as recited in claim 11 wherein the adjusting and deflecting means comprise an extension of the bar beyond the pivot axis of the door and adjustable compression and tension members secure the bar to the remainder of the'trolley on opposite sides of the pivot axis.

13. A device as recited in claim 20 wherein the cantilever mounting connection is constructed and arranged to have a section modulus sufficient to serve as the sole support for the unbalanced weight of the door panel as the same is moved from its position parallel with the rack.

14. A device as recited in claim 13 including a swinging side panel having a fixed pivot axis disposed substantially parallel to the pivot axis of the cantilever mounting connection, said side panel being positioned in a plane parallel to the door panel and having its free edge disposed in overlapping relationship with the cantilever mounting connection when the door panel is in its closed position so that its free edge is automatically engaged by the door panel during the swinging movement thereof and the door panel may be swung open at any position in its movement along the track.

15. A device as recited in claim 14 including means for normally holding the side panel in its closed position.

16. A device as recited in claim 15 wherein the holding means provides a continuous bias urging the side panel to its closed position.

17. A device as recited in claim 14 wherein a power operator is provided for powering the door panel during its normal movement along the track and the controls therefor include means associated with a lock for the side panel to render the power operator inoperative when the lock is secured.

18. A sliding door assembly comprising a track, a trolley supported by said track, a sliding door mounted by the trolley for movement along the track and including a cantilever mounted door panel supported for swinging movement about a first pivot axis substantially perpendicular to the track, and a swinging side panel having a second pivot axis disposed substantially parallel to said first pivot axis, said side panel being offset from said door panel and disposed along a plane parallel thereto, the sliding door being movable toward said second pivot axis during its opening movement and the free edge of the side panel being engaged by the door panel References Cited UNITED STATES PATENTS 1,852,608 4/1932 Grable 49125 X 2,386,510 10/1945 Shafer 49149 X 2,649,612 8/1953 Loomis l694 3,300,897 1/1967 Wikkering 49177 X 3,327,428 6/ 1967 Horton et al 49177 3,354,581 11/1967 Dimmitt et a1 49-141 FOREIGN PATENTS 692,399 8/ 1964 Canada.

DENNIS L. TAYLOR, Primary Examiner US. or. X.R. 7 49-163, 410 

